type The post type, can be one of the following
* regular
* photo
* quote
* link
* conversation
* video
* audio
See below about the additional parameters associated with each type
date (optional) The post date, if different from now, in the blog's timezone
Most unambiguous formats are accepted, such as '2007-12-01 14:50:02'
Dates may not be in the future
private (optional) 1 or 0 (Whether the post is private)
Private posts only appear in the dashboard or with authenticated links, and do not appear on the blog's main page
tags (optional) Comma-separated list of post tags
You may optionally enclose tags in double-quotes
format (optional) 'html' or 'markdown'
group (optional) Post this to a secondary blog on your account, e.g. mygroup.tumblr.com (for public groups only)
slug (optional) A custom string to appear in the post's URL: myblog.tumblr.com/post/123456/this-string-right-here
URL-friendly formatting will be applied automatically
Maximum of 55 characters
state (optional) One of the following values:
* published (default)
* draft - Save in the drafts folder for later publishing
* submission - Add to the messages folder for consideration
* queue - Add to the queue for automatic publishing in a few minutes or hours
To publish at a specific time in the future instead, specify an additional publish-on parameter
with the date expression in the local time of the blog (e.g. publish-on=2010-01-01T13:34:00)
If the date format cannot be understood, a 401 error will be returned and the post will not be created
To change the state of an existing post, such as to switch from draft to published,
follow the editing process and pass the new value as the state parameter
Note: If a post has previously been saved as a draft, queue, or submission post,
it will be assigned a new post ID the first time it enters the published state.

Depending on the kind of post (type), additional parameters will be necessary: